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![Ming Lei](/assets/img/avatar_default.png)
Some HDD drive may expose multiple hardware queues, such as MegraRaid. Let's apply the normal plugging for such devices because sequential IO may benefit a lot from plug merging. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Dave Chinner <dchinner@redhat.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
3552 lines
86 KiB
C
3552 lines
86 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Block multiqueue core code
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*
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* Copyright (C) 2013-2014 Jens Axboe
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* Copyright (C) 2013-2014 Christoph Hellwig
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/kmemleak.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/smp.h>
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#include <linux/llist.h>
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#include <linux/list_sort.h>
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#include <linux/cpu.h>
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#include <linux/cache.h>
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#include <linux/sched/sysctl.h>
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#include <linux/sched/topology.h>
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#include <linux/sched/signal.h>
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#include <linux/delay.h>
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#include <linux/crash_dump.h>
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#include <linux/prefetch.h>
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#include <trace/events/block.h>
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#include <linux/blk-mq.h>
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#include <linux/t10-pi.h>
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#include "blk.h"
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#include "blk-mq.h"
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#include "blk-mq-debugfs.h"
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#include "blk-mq-tag.h"
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#include "blk-pm.h"
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#include "blk-stat.h"
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#include "blk-mq-sched.h"
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#include "blk-rq-qos.h"
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static void blk_mq_poll_stats_start(struct request_queue *q);
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static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
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static int blk_mq_poll_stats_bkt(const struct request *rq)
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{
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int ddir, sectors, bucket;
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ddir = rq_data_dir(rq);
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sectors = blk_rq_stats_sectors(rq);
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bucket = ddir + 2 * ilog2(sectors);
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if (bucket < 0)
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return -1;
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else if (bucket >= BLK_MQ_POLL_STATS_BKTS)
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return ddir + BLK_MQ_POLL_STATS_BKTS - 2;
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return bucket;
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}
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/*
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* Check if any of the ctx, dispatch list or elevator
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* have pending work in this hardware queue.
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*/
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static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
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{
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return !list_empty_careful(&hctx->dispatch) ||
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sbitmap_any_bit_set(&hctx->ctx_map) ||
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blk_mq_sched_has_work(hctx);
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}
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/*
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* Mark this ctx as having pending work in this hardware queue
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*/
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static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
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struct blk_mq_ctx *ctx)
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{
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const int bit = ctx->index_hw[hctx->type];
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if (!sbitmap_test_bit(&hctx->ctx_map, bit))
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sbitmap_set_bit(&hctx->ctx_map, bit);
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}
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static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
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struct blk_mq_ctx *ctx)
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{
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const int bit = ctx->index_hw[hctx->type];
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sbitmap_clear_bit(&hctx->ctx_map, bit);
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}
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struct mq_inflight {
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struct hd_struct *part;
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unsigned int *inflight;
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};
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static bool blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
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struct request *rq, void *priv,
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bool reserved)
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{
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struct mq_inflight *mi = priv;
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/*
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* index[0] counts the specific partition that was asked for.
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*/
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if (rq->part == mi->part)
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mi->inflight[0]++;
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return true;
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}
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unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part)
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{
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unsigned inflight[2];
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struct mq_inflight mi = { .part = part, .inflight = inflight, };
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inflight[0] = inflight[1] = 0;
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blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
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return inflight[0];
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}
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static bool blk_mq_check_inflight_rw(struct blk_mq_hw_ctx *hctx,
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struct request *rq, void *priv,
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bool reserved)
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{
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struct mq_inflight *mi = priv;
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if (rq->part == mi->part)
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mi->inflight[rq_data_dir(rq)]++;
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return true;
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}
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void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
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unsigned int inflight[2])
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{
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struct mq_inflight mi = { .part = part, .inflight = inflight, };
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inflight[0] = inflight[1] = 0;
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blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight_rw, &mi);
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}
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void blk_freeze_queue_start(struct request_queue *q)
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{
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mutex_lock(&q->mq_freeze_lock);
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if (++q->mq_freeze_depth == 1) {
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percpu_ref_kill(&q->q_usage_counter);
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mutex_unlock(&q->mq_freeze_lock);
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if (queue_is_mq(q))
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blk_mq_run_hw_queues(q, false);
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} else {
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mutex_unlock(&q->mq_freeze_lock);
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}
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}
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EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
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void blk_mq_freeze_queue_wait(struct request_queue *q)
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{
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wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
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}
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
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int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
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unsigned long timeout)
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{
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return wait_event_timeout(q->mq_freeze_wq,
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percpu_ref_is_zero(&q->q_usage_counter),
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timeout);
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}
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
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/*
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* Guarantee no request is in use, so we can change any data structure of
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* the queue afterward.
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*/
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void blk_freeze_queue(struct request_queue *q)
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{
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/*
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* In the !blk_mq case we are only calling this to kill the
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* q_usage_counter, otherwise this increases the freeze depth
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* and waits for it to return to zero. For this reason there is
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* no blk_unfreeze_queue(), and blk_freeze_queue() is not
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* exported to drivers as the only user for unfreeze is blk_mq.
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*/
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blk_freeze_queue_start(q);
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blk_mq_freeze_queue_wait(q);
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}
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void blk_mq_freeze_queue(struct request_queue *q)
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{
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/*
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* ...just an alias to keep freeze and unfreeze actions balanced
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* in the blk_mq_* namespace
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*/
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blk_freeze_queue(q);
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}
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
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void blk_mq_unfreeze_queue(struct request_queue *q)
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{
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mutex_lock(&q->mq_freeze_lock);
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q->mq_freeze_depth--;
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WARN_ON_ONCE(q->mq_freeze_depth < 0);
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if (!q->mq_freeze_depth) {
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percpu_ref_resurrect(&q->q_usage_counter);
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wake_up_all(&q->mq_freeze_wq);
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}
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mutex_unlock(&q->mq_freeze_lock);
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}
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EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
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/*
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* FIXME: replace the scsi_internal_device_*block_nowait() calls in the
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* mpt3sas driver such that this function can be removed.
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*/
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void blk_mq_quiesce_queue_nowait(struct request_queue *q)
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{
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blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
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}
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EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
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/**
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* blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
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* @q: request queue.
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*
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* Note: this function does not prevent that the struct request end_io()
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* callback function is invoked. Once this function is returned, we make
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* sure no dispatch can happen until the queue is unquiesced via
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* blk_mq_unquiesce_queue().
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*/
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void blk_mq_quiesce_queue(struct request_queue *q)
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{
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struct blk_mq_hw_ctx *hctx;
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unsigned int i;
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bool rcu = false;
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blk_mq_quiesce_queue_nowait(q);
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queue_for_each_hw_ctx(q, hctx, i) {
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if (hctx->flags & BLK_MQ_F_BLOCKING)
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synchronize_srcu(hctx->srcu);
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else
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rcu = true;
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}
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if (rcu)
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
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/*
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* blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
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* @q: request queue.
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*
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* This function recovers queue into the state before quiescing
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* which is done by blk_mq_quiesce_queue.
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*/
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void blk_mq_unquiesce_queue(struct request_queue *q)
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{
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blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
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/* dispatch requests which are inserted during quiescing */
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blk_mq_run_hw_queues(q, true);
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}
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EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
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void blk_mq_wake_waiters(struct request_queue *q)
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{
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struct blk_mq_hw_ctx *hctx;
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unsigned int i;
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queue_for_each_hw_ctx(q, hctx, i)
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if (blk_mq_hw_queue_mapped(hctx))
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blk_mq_tag_wakeup_all(hctx->tags, true);
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}
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bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
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{
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return blk_mq_has_free_tags(hctx->tags);
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}
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EXPORT_SYMBOL(blk_mq_can_queue);
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/*
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* Only need start/end time stamping if we have iostat or
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* blk stats enabled, or using an IO scheduler.
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*/
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static inline bool blk_mq_need_time_stamp(struct request *rq)
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{
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return (rq->rq_flags & (RQF_IO_STAT | RQF_STATS)) || rq->q->elevator;
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}
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static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
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unsigned int tag, unsigned int op, u64 alloc_time_ns)
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{
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struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
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struct request *rq = tags->static_rqs[tag];
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req_flags_t rq_flags = 0;
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if (data->flags & BLK_MQ_REQ_INTERNAL) {
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rq->tag = -1;
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rq->internal_tag = tag;
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} else {
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if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) {
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rq_flags = RQF_MQ_INFLIGHT;
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atomic_inc(&data->hctx->nr_active);
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}
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rq->tag = tag;
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rq->internal_tag = -1;
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data->hctx->tags->rqs[rq->tag] = rq;
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}
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/* csd/requeue_work/fifo_time is initialized before use */
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rq->q = data->q;
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rq->mq_ctx = data->ctx;
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rq->mq_hctx = data->hctx;
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rq->rq_flags = rq_flags;
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rq->cmd_flags = op;
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if (data->flags & BLK_MQ_REQ_PREEMPT)
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rq->rq_flags |= RQF_PREEMPT;
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if (blk_queue_io_stat(data->q))
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rq->rq_flags |= RQF_IO_STAT;
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INIT_LIST_HEAD(&rq->queuelist);
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INIT_HLIST_NODE(&rq->hash);
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RB_CLEAR_NODE(&rq->rb_node);
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rq->rq_disk = NULL;
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rq->part = NULL;
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#ifdef CONFIG_BLK_RQ_ALLOC_TIME
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rq->alloc_time_ns = alloc_time_ns;
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#endif
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if (blk_mq_need_time_stamp(rq))
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rq->start_time_ns = ktime_get_ns();
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else
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rq->start_time_ns = 0;
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rq->io_start_time_ns = 0;
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rq->stats_sectors = 0;
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rq->nr_phys_segments = 0;
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#if defined(CONFIG_BLK_DEV_INTEGRITY)
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rq->nr_integrity_segments = 0;
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#endif
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/* tag was already set */
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rq->extra_len = 0;
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WRITE_ONCE(rq->deadline, 0);
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rq->timeout = 0;
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rq->end_io = NULL;
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rq->end_io_data = NULL;
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data->ctx->rq_dispatched[op_is_sync(op)]++;
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refcount_set(&rq->ref, 1);
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return rq;
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}
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static struct request *blk_mq_get_request(struct request_queue *q,
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struct bio *bio,
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struct blk_mq_alloc_data *data)
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{
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struct elevator_queue *e = q->elevator;
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struct request *rq;
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unsigned int tag;
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bool clear_ctx_on_error = false;
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u64 alloc_time_ns = 0;
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blk_queue_enter_live(q);
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/* alloc_time includes depth and tag waits */
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if (blk_queue_rq_alloc_time(q))
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alloc_time_ns = ktime_get_ns();
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data->q = q;
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if (likely(!data->ctx)) {
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data->ctx = blk_mq_get_ctx(q);
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clear_ctx_on_error = true;
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}
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if (likely(!data->hctx))
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data->hctx = blk_mq_map_queue(q, data->cmd_flags,
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data->ctx);
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if (data->cmd_flags & REQ_NOWAIT)
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data->flags |= BLK_MQ_REQ_NOWAIT;
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if (e) {
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data->flags |= BLK_MQ_REQ_INTERNAL;
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/*
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* Flush requests are special and go directly to the
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* dispatch list. Don't include reserved tags in the
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* limiting, as it isn't useful.
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*/
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if (!op_is_flush(data->cmd_flags) &&
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e->type->ops.limit_depth &&
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!(data->flags & BLK_MQ_REQ_RESERVED))
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e->type->ops.limit_depth(data->cmd_flags, data);
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} else {
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blk_mq_tag_busy(data->hctx);
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}
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tag = blk_mq_get_tag(data);
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if (tag == BLK_MQ_TAG_FAIL) {
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if (clear_ctx_on_error)
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data->ctx = NULL;
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blk_queue_exit(q);
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return NULL;
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}
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rq = blk_mq_rq_ctx_init(data, tag, data->cmd_flags, alloc_time_ns);
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if (!op_is_flush(data->cmd_flags)) {
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rq->elv.icq = NULL;
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if (e && e->type->ops.prepare_request) {
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if (e->type->icq_cache)
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blk_mq_sched_assign_ioc(rq);
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e->type->ops.prepare_request(rq, bio);
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rq->rq_flags |= RQF_ELVPRIV;
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}
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}
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data->hctx->queued++;
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return rq;
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}
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struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
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blk_mq_req_flags_t flags)
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{
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struct blk_mq_alloc_data alloc_data = { .flags = flags, .cmd_flags = op };
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struct request *rq;
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int ret;
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ret = blk_queue_enter(q, flags);
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if (ret)
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return ERR_PTR(ret);
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rq = blk_mq_get_request(q, NULL, &alloc_data);
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blk_queue_exit(q);
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if (!rq)
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return ERR_PTR(-EWOULDBLOCK);
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rq->__data_len = 0;
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rq->__sector = (sector_t) -1;
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rq->bio = rq->biotail = NULL;
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return rq;
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}
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EXPORT_SYMBOL(blk_mq_alloc_request);
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struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
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unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx)
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{
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struct blk_mq_alloc_data alloc_data = { .flags = flags, .cmd_flags = op };
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struct request *rq;
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unsigned int cpu;
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int ret;
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/*
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* If the tag allocator sleeps we could get an allocation for a
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* different hardware context. No need to complicate the low level
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* allocator for this for the rare use case of a command tied to
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* a specific queue.
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*/
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if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)))
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return ERR_PTR(-EINVAL);
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if (hctx_idx >= q->nr_hw_queues)
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return ERR_PTR(-EIO);
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ret = blk_queue_enter(q, flags);
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if (ret)
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return ERR_PTR(ret);
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/*
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* Check if the hardware context is actually mapped to anything.
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* If not tell the caller that it should skip this queue.
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*/
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alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
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if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {
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blk_queue_exit(q);
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return ERR_PTR(-EXDEV);
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}
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cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask);
|
|
alloc_data.ctx = __blk_mq_get_ctx(q, cpu);
|
|
|
|
rq = blk_mq_get_request(q, NULL, &alloc_data);
|
|
blk_queue_exit(q);
|
|
|
|
if (!rq)
|
|
return ERR_PTR(-EWOULDBLOCK);
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
|
|
|
|
static void __blk_mq_free_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
|
|
const int sched_tag = rq->internal_tag;
|
|
|
|
blk_pm_mark_last_busy(rq);
|
|
rq->mq_hctx = NULL;
|
|
if (rq->tag != -1)
|
|
blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
|
|
if (sched_tag != -1)
|
|
blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag);
|
|
blk_mq_sched_restart(hctx);
|
|
blk_queue_exit(q);
|
|
}
|
|
|
|
void blk_mq_free_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct elevator_queue *e = q->elevator;
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
|
|
|
|
if (rq->rq_flags & RQF_ELVPRIV) {
|
|
if (e && e->type->ops.finish_request)
|
|
e->type->ops.finish_request(rq);
|
|
if (rq->elv.icq) {
|
|
put_io_context(rq->elv.icq->ioc);
|
|
rq->elv.icq = NULL;
|
|
}
|
|
}
|
|
|
|
ctx->rq_completed[rq_is_sync(rq)]++;
|
|
if (rq->rq_flags & RQF_MQ_INFLIGHT)
|
|
atomic_dec(&hctx->nr_active);
|
|
|
|
if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
|
|
laptop_io_completion(q->backing_dev_info);
|
|
|
|
rq_qos_done(q, rq);
|
|
|
|
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
|
|
if (refcount_dec_and_test(&rq->ref))
|
|
__blk_mq_free_request(rq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_free_request);
|
|
|
|
inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
|
|
{
|
|
u64 now = 0;
|
|
|
|
if (blk_mq_need_time_stamp(rq))
|
|
now = ktime_get_ns();
|
|
|
|
if (rq->rq_flags & RQF_STATS) {
|
|
blk_mq_poll_stats_start(rq->q);
|
|
blk_stat_add(rq, now);
|
|
}
|
|
|
|
if (rq->internal_tag != -1)
|
|
blk_mq_sched_completed_request(rq, now);
|
|
|
|
blk_account_io_done(rq, now);
|
|
|
|
if (rq->end_io) {
|
|
rq_qos_done(rq->q, rq);
|
|
rq->end_io(rq, error);
|
|
} else {
|
|
blk_mq_free_request(rq);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(__blk_mq_end_request);
|
|
|
|
void blk_mq_end_request(struct request *rq, blk_status_t error)
|
|
{
|
|
if (blk_update_request(rq, error, blk_rq_bytes(rq)))
|
|
BUG();
|
|
__blk_mq_end_request(rq, error);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_end_request);
|
|
|
|
static void __blk_mq_complete_request_remote(void *data)
|
|
{
|
|
struct request *rq = data;
|
|
struct request_queue *q = rq->q;
|
|
|
|
q->mq_ops->complete(rq);
|
|
}
|
|
|
|
static void __blk_mq_complete_request(struct request *rq)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
struct request_queue *q = rq->q;
|
|
bool shared = false;
|
|
int cpu;
|
|
|
|
WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
|
|
/*
|
|
* Most of single queue controllers, there is only one irq vector
|
|
* for handling IO completion, and the only irq's affinity is set
|
|
* as all possible CPUs. On most of ARCHs, this affinity means the
|
|
* irq is handled on one specific CPU.
|
|
*
|
|
* So complete IO reqeust in softirq context in case of single queue
|
|
* for not degrading IO performance by irqsoff latency.
|
|
*/
|
|
if (q->nr_hw_queues == 1) {
|
|
__blk_complete_request(rq);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* For a polled request, always complete locallly, it's pointless
|
|
* to redirect the completion.
|
|
*/
|
|
if ((rq->cmd_flags & REQ_HIPRI) ||
|
|
!test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) {
|
|
q->mq_ops->complete(rq);
|
|
return;
|
|
}
|
|
|
|
cpu = get_cpu();
|
|
if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
|
|
shared = cpus_share_cache(cpu, ctx->cpu);
|
|
|
|
if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
|
|
rq->csd.func = __blk_mq_complete_request_remote;
|
|
rq->csd.info = rq;
|
|
rq->csd.flags = 0;
|
|
smp_call_function_single_async(ctx->cpu, &rq->csd);
|
|
} else {
|
|
q->mq_ops->complete(rq);
|
|
}
|
|
put_cpu();
|
|
}
|
|
|
|
static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
|
|
__releases(hctx->srcu)
|
|
{
|
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING))
|
|
rcu_read_unlock();
|
|
else
|
|
srcu_read_unlock(hctx->srcu, srcu_idx);
|
|
}
|
|
|
|
static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx)
|
|
__acquires(hctx->srcu)
|
|
{
|
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
/* shut up gcc false positive */
|
|
*srcu_idx = 0;
|
|
rcu_read_lock();
|
|
} else
|
|
*srcu_idx = srcu_read_lock(hctx->srcu);
|
|
}
|
|
|
|
/**
|
|
* blk_mq_complete_request - end I/O on a request
|
|
* @rq: the request being processed
|
|
*
|
|
* Description:
|
|
* Ends all I/O on a request. It does not handle partial completions.
|
|
* The actual completion happens out-of-order, through a IPI handler.
|
|
**/
|
|
bool blk_mq_complete_request(struct request *rq)
|
|
{
|
|
if (unlikely(blk_should_fake_timeout(rq->q)))
|
|
return false;
|
|
__blk_mq_complete_request(rq);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_complete_request);
|
|
|
|
int blk_mq_request_started(struct request *rq)
|
|
{
|
|
return blk_mq_rq_state(rq) != MQ_RQ_IDLE;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_request_started);
|
|
|
|
int blk_mq_request_completed(struct request *rq)
|
|
{
|
|
return blk_mq_rq_state(rq) == MQ_RQ_COMPLETE;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_request_completed);
|
|
|
|
void blk_mq_start_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
trace_block_rq_issue(q, rq);
|
|
|
|
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
|
|
rq->io_start_time_ns = ktime_get_ns();
|
|
rq->stats_sectors = blk_rq_sectors(rq);
|
|
rq->rq_flags |= RQF_STATS;
|
|
rq_qos_issue(q, rq);
|
|
}
|
|
|
|
WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
|
|
|
|
blk_add_timer(rq);
|
|
WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
|
|
|
|
if (q->dma_drain_size && blk_rq_bytes(rq)) {
|
|
/*
|
|
* Make sure space for the drain appears. We know we can do
|
|
* this because max_hw_segments has been adjusted to be one
|
|
* fewer than the device can handle.
|
|
*/
|
|
rq->nr_phys_segments++;
|
|
}
|
|
|
|
#ifdef CONFIG_BLK_DEV_INTEGRITY
|
|
if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
|
|
q->integrity.profile->prepare_fn(rq);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_request);
|
|
|
|
static void __blk_mq_requeue_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
blk_mq_put_driver_tag(rq);
|
|
|
|
trace_block_rq_requeue(q, rq);
|
|
rq_qos_requeue(q, rq);
|
|
|
|
if (blk_mq_request_started(rq)) {
|
|
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
|
|
rq->rq_flags &= ~RQF_TIMED_OUT;
|
|
if (q->dma_drain_size && blk_rq_bytes(rq))
|
|
rq->nr_phys_segments--;
|
|
}
|
|
}
|
|
|
|
void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
|
|
{
|
|
__blk_mq_requeue_request(rq);
|
|
|
|
/* this request will be re-inserted to io scheduler queue */
|
|
blk_mq_sched_requeue_request(rq);
|
|
|
|
BUG_ON(!list_empty(&rq->queuelist));
|
|
blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_requeue_request);
|
|
|
|
static void blk_mq_requeue_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, requeue_work.work);
|
|
LIST_HEAD(rq_list);
|
|
struct request *rq, *next;
|
|
|
|
spin_lock_irq(&q->requeue_lock);
|
|
list_splice_init(&q->requeue_list, &rq_list);
|
|
spin_unlock_irq(&q->requeue_lock);
|
|
|
|
list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
|
|
if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP)))
|
|
continue;
|
|
|
|
rq->rq_flags &= ~RQF_SOFTBARRIER;
|
|
list_del_init(&rq->queuelist);
|
|
/*
|
|
* If RQF_DONTPREP, rq has contained some driver specific
|
|
* data, so insert it to hctx dispatch list to avoid any
|
|
* merge.
|
|
*/
|
|
if (rq->rq_flags & RQF_DONTPREP)
|
|
blk_mq_request_bypass_insert(rq, false);
|
|
else
|
|
blk_mq_sched_insert_request(rq, true, false, false);
|
|
}
|
|
|
|
while (!list_empty(&rq_list)) {
|
|
rq = list_entry(rq_list.next, struct request, queuelist);
|
|
list_del_init(&rq->queuelist);
|
|
blk_mq_sched_insert_request(rq, false, false, false);
|
|
}
|
|
|
|
blk_mq_run_hw_queues(q, false);
|
|
}
|
|
|
|
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
|
|
bool kick_requeue_list)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* We abuse this flag that is otherwise used by the I/O scheduler to
|
|
* request head insertion from the workqueue.
|
|
*/
|
|
BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
|
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags);
|
|
if (at_head) {
|
|
rq->rq_flags |= RQF_SOFTBARRIER;
|
|
list_add(&rq->queuelist, &q->requeue_list);
|
|
} else {
|
|
list_add_tail(&rq->queuelist, &q->requeue_list);
|
|
}
|
|
spin_unlock_irqrestore(&q->requeue_lock, flags);
|
|
|
|
if (kick_requeue_list)
|
|
blk_mq_kick_requeue_list(q);
|
|
}
|
|
|
|
void blk_mq_kick_requeue_list(struct request_queue *q)
|
|
{
|
|
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_kick_requeue_list);
|
|
|
|
void blk_mq_delay_kick_requeue_list(struct request_queue *q,
|
|
unsigned long msecs)
|
|
{
|
|
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
|
|
|
|
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
|
|
{
|
|
if (tag < tags->nr_tags) {
|
|
prefetch(tags->rqs[tag]);
|
|
return tags->rqs[tag];
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_tag_to_rq);
|
|
|
|
static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq,
|
|
void *priv, bool reserved)
|
|
{
|
|
/*
|
|
* If we find a request that is inflight and the queue matches,
|
|
* we know the queue is busy. Return false to stop the iteration.
|
|
*/
|
|
if (rq->state == MQ_RQ_IN_FLIGHT && rq->q == hctx->queue) {
|
|
bool *busy = priv;
|
|
|
|
*busy = true;
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
bool blk_mq_queue_inflight(struct request_queue *q)
|
|
{
|
|
bool busy = false;
|
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
|
|
return busy;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
|
|
|
|
static void blk_mq_rq_timed_out(struct request *req, bool reserved)
|
|
{
|
|
req->rq_flags |= RQF_TIMED_OUT;
|
|
if (req->q->mq_ops->timeout) {
|
|
enum blk_eh_timer_return ret;
|
|
|
|
ret = req->q->mq_ops->timeout(req, reserved);
|
|
if (ret == BLK_EH_DONE)
|
|
return;
|
|
WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
|
|
}
|
|
|
|
blk_add_timer(req);
|
|
}
|
|
|
|
static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
|
|
{
|
|
unsigned long deadline;
|
|
|
|
if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
|
|
return false;
|
|
if (rq->rq_flags & RQF_TIMED_OUT)
|
|
return false;
|
|
|
|
deadline = READ_ONCE(rq->deadline);
|
|
if (time_after_eq(jiffies, deadline))
|
|
return true;
|
|
|
|
if (*next == 0)
|
|
*next = deadline;
|
|
else if (time_after(*next, deadline))
|
|
*next = deadline;
|
|
return false;
|
|
}
|
|
|
|
static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, void *priv, bool reserved)
|
|
{
|
|
unsigned long *next = priv;
|
|
|
|
/*
|
|
* Just do a quick check if it is expired before locking the request in
|
|
* so we're not unnecessarilly synchronizing across CPUs.
|
|
*/
|
|
if (!blk_mq_req_expired(rq, next))
|
|
return true;
|
|
|
|
/*
|
|
* We have reason to believe the request may be expired. Take a
|
|
* reference on the request to lock this request lifetime into its
|
|
* currently allocated context to prevent it from being reallocated in
|
|
* the event the completion by-passes this timeout handler.
|
|
*
|
|
* If the reference was already released, then the driver beat the
|
|
* timeout handler to posting a natural completion.
|
|
*/
|
|
if (!refcount_inc_not_zero(&rq->ref))
|
|
return true;
|
|
|
|
/*
|
|
* The request is now locked and cannot be reallocated underneath the
|
|
* timeout handler's processing. Re-verify this exact request is truly
|
|
* expired; if it is not expired, then the request was completed and
|
|
* reallocated as a new request.
|
|
*/
|
|
if (blk_mq_req_expired(rq, next))
|
|
blk_mq_rq_timed_out(rq, reserved);
|
|
|
|
if (is_flush_rq(rq, hctx))
|
|
rq->end_io(rq, 0);
|
|
else if (refcount_dec_and_test(&rq->ref))
|
|
__blk_mq_free_request(rq);
|
|
|
|
return true;
|
|
}
|
|
|
|
static void blk_mq_timeout_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, timeout_work);
|
|
unsigned long next = 0;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
/* A deadlock might occur if a request is stuck requiring a
|
|
* timeout at the same time a queue freeze is waiting
|
|
* completion, since the timeout code would not be able to
|
|
* acquire the queue reference here.
|
|
*
|
|
* That's why we don't use blk_queue_enter here; instead, we use
|
|
* percpu_ref_tryget directly, because we need to be able to
|
|
* obtain a reference even in the short window between the queue
|
|
* starting to freeze, by dropping the first reference in
|
|
* blk_freeze_queue_start, and the moment the last request is
|
|
* consumed, marked by the instant q_usage_counter reaches
|
|
* zero.
|
|
*/
|
|
if (!percpu_ref_tryget(&q->q_usage_counter))
|
|
return;
|
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next);
|
|
|
|
if (next != 0) {
|
|
mod_timer(&q->timeout, next);
|
|
} else {
|
|
/*
|
|
* Request timeouts are handled as a forward rolling timer. If
|
|
* we end up here it means that no requests are pending and
|
|
* also that no request has been pending for a while. Mark
|
|
* each hctx as idle.
|
|
*/
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/* the hctx may be unmapped, so check it here */
|
|
if (blk_mq_hw_queue_mapped(hctx))
|
|
blk_mq_tag_idle(hctx);
|
|
}
|
|
}
|
|
blk_queue_exit(q);
|
|
}
|
|
|
|
struct flush_busy_ctx_data {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct list_head *list;
|
|
};
|
|
|
|
static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
|
|
{
|
|
struct flush_busy_ctx_data *flush_data = data;
|
|
struct blk_mq_hw_ctx *hctx = flush_data->hctx;
|
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
|
|
enum hctx_type type = hctx->type;
|
|
|
|
spin_lock(&ctx->lock);
|
|
list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
|
|
sbitmap_clear_bit(sb, bitnr);
|
|
spin_unlock(&ctx->lock);
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Process software queues that have been marked busy, splicing them
|
|
* to the for-dispatch
|
|
*/
|
|
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
|
|
{
|
|
struct flush_busy_ctx_data data = {
|
|
.hctx = hctx,
|
|
.list = list,
|
|
};
|
|
|
|
sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
|
|
|
|
struct dispatch_rq_data {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request *rq;
|
|
};
|
|
|
|
static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
|
|
void *data)
|
|
{
|
|
struct dispatch_rq_data *dispatch_data = data;
|
|
struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
|
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
|
|
enum hctx_type type = hctx->type;
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (!list_empty(&ctx->rq_lists[type])) {
|
|
dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
|
|
list_del_init(&dispatch_data->rq->queuelist);
|
|
if (list_empty(&ctx->rq_lists[type]))
|
|
sbitmap_clear_bit(sb, bitnr);
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
|
|
return !dispatch_data->rq;
|
|
}
|
|
|
|
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *start)
|
|
{
|
|
unsigned off = start ? start->index_hw[hctx->type] : 0;
|
|
struct dispatch_rq_data data = {
|
|
.hctx = hctx,
|
|
.rq = NULL,
|
|
};
|
|
|
|
__sbitmap_for_each_set(&hctx->ctx_map, off,
|
|
dispatch_rq_from_ctx, &data);
|
|
|
|
return data.rq;
|
|
}
|
|
|
|
static inline unsigned int queued_to_index(unsigned int queued)
|
|
{
|
|
if (!queued)
|
|
return 0;
|
|
|
|
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
|
|
}
|
|
|
|
bool blk_mq_get_driver_tag(struct request *rq)
|
|
{
|
|
struct blk_mq_alloc_data data = {
|
|
.q = rq->q,
|
|
.hctx = rq->mq_hctx,
|
|
.flags = BLK_MQ_REQ_NOWAIT,
|
|
.cmd_flags = rq->cmd_flags,
|
|
};
|
|
bool shared;
|
|
|
|
if (rq->tag != -1)
|
|
goto done;
|
|
|
|
if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag))
|
|
data.flags |= BLK_MQ_REQ_RESERVED;
|
|
|
|
shared = blk_mq_tag_busy(data.hctx);
|
|
rq->tag = blk_mq_get_tag(&data);
|
|
if (rq->tag >= 0) {
|
|
if (shared) {
|
|
rq->rq_flags |= RQF_MQ_INFLIGHT;
|
|
atomic_inc(&data.hctx->nr_active);
|
|
}
|
|
data.hctx->tags->rqs[rq->tag] = rq;
|
|
}
|
|
|
|
done:
|
|
return rq->tag != -1;
|
|
}
|
|
|
|
static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
|
|
int flags, void *key)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
|
|
|
|
spin_lock(&hctx->dispatch_wait_lock);
|
|
if (!list_empty(&wait->entry)) {
|
|
struct sbitmap_queue *sbq;
|
|
|
|
list_del_init(&wait->entry);
|
|
sbq = &hctx->tags->bitmap_tags;
|
|
atomic_dec(&sbq->ws_active);
|
|
}
|
|
spin_unlock(&hctx->dispatch_wait_lock);
|
|
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Mark us waiting for a tag. For shared tags, this involves hooking us into
|
|
* the tag wakeups. For non-shared tags, we can simply mark us needing a
|
|
* restart. For both cases, take care to check the condition again after
|
|
* marking us as waiting.
|
|
*/
|
|
static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags;
|
|
struct wait_queue_head *wq;
|
|
wait_queue_entry_t *wait;
|
|
bool ret;
|
|
|
|
if (!(hctx->flags & BLK_MQ_F_TAG_SHARED)) {
|
|
blk_mq_sched_mark_restart_hctx(hctx);
|
|
|
|
/*
|
|
* It's possible that a tag was freed in the window between the
|
|
* allocation failure and adding the hardware queue to the wait
|
|
* queue.
|
|
*
|
|
* Don't clear RESTART here, someone else could have set it.
|
|
* At most this will cost an extra queue run.
|
|
*/
|
|
return blk_mq_get_driver_tag(rq);
|
|
}
|
|
|
|
wait = &hctx->dispatch_wait;
|
|
if (!list_empty_careful(&wait->entry))
|
|
return false;
|
|
|
|
wq = &bt_wait_ptr(sbq, hctx)->wait;
|
|
|
|
spin_lock_irq(&wq->lock);
|
|
spin_lock(&hctx->dispatch_wait_lock);
|
|
if (!list_empty(&wait->entry)) {
|
|
spin_unlock(&hctx->dispatch_wait_lock);
|
|
spin_unlock_irq(&wq->lock);
|
|
return false;
|
|
}
|
|
|
|
atomic_inc(&sbq->ws_active);
|
|
wait->flags &= ~WQ_FLAG_EXCLUSIVE;
|
|
__add_wait_queue(wq, wait);
|
|
|
|
/*
|
|
* It's possible that a tag was freed in the window between the
|
|
* allocation failure and adding the hardware queue to the wait
|
|
* queue.
|
|
*/
|
|
ret = blk_mq_get_driver_tag(rq);
|
|
if (!ret) {
|
|
spin_unlock(&hctx->dispatch_wait_lock);
|
|
spin_unlock_irq(&wq->lock);
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* We got a tag, remove ourselves from the wait queue to ensure
|
|
* someone else gets the wakeup.
|
|
*/
|
|
list_del_init(&wait->entry);
|
|
atomic_dec(&sbq->ws_active);
|
|
spin_unlock(&hctx->dispatch_wait_lock);
|
|
spin_unlock_irq(&wq->lock);
|
|
|
|
return true;
|
|
}
|
|
|
|
#define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
|
|
#define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
|
|
/*
|
|
* Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
|
|
* - EWMA is one simple way to compute running average value
|
|
* - weight(7/8 and 1/8) is applied so that it can decrease exponentially
|
|
* - take 4 as factor for avoiding to get too small(0) result, and this
|
|
* factor doesn't matter because EWMA decreases exponentially
|
|
*/
|
|
static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
|
|
{
|
|
unsigned int ewma;
|
|
|
|
if (hctx->queue->elevator)
|
|
return;
|
|
|
|
ewma = hctx->dispatch_busy;
|
|
|
|
if (!ewma && !busy)
|
|
return;
|
|
|
|
ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
|
|
if (busy)
|
|
ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
|
|
ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
|
|
|
|
hctx->dispatch_busy = ewma;
|
|
}
|
|
|
|
#define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
|
|
|
|
/*
|
|
* Returns true if we did some work AND can potentially do more.
|
|
*/
|
|
bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
|
|
bool got_budget)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request *rq, *nxt;
|
|
bool no_tag = false;
|
|
int errors, queued;
|
|
blk_status_t ret = BLK_STS_OK;
|
|
|
|
if (list_empty(list))
|
|
return false;
|
|
|
|
WARN_ON(!list_is_singular(list) && got_budget);
|
|
|
|
/*
|
|
* Now process all the entries, sending them to the driver.
|
|
*/
|
|
errors = queued = 0;
|
|
do {
|
|
struct blk_mq_queue_data bd;
|
|
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
|
|
hctx = rq->mq_hctx;
|
|
if (!got_budget && !blk_mq_get_dispatch_budget(hctx))
|
|
break;
|
|
|
|
if (!blk_mq_get_driver_tag(rq)) {
|
|
/*
|
|
* The initial allocation attempt failed, so we need to
|
|
* rerun the hardware queue when a tag is freed. The
|
|
* waitqueue takes care of that. If the queue is run
|
|
* before we add this entry back on the dispatch list,
|
|
* we'll re-run it below.
|
|
*/
|
|
if (!blk_mq_mark_tag_wait(hctx, rq)) {
|
|
blk_mq_put_dispatch_budget(hctx);
|
|
/*
|
|
* For non-shared tags, the RESTART check
|
|
* will suffice.
|
|
*/
|
|
if (hctx->flags & BLK_MQ_F_TAG_SHARED)
|
|
no_tag = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
list_del_init(&rq->queuelist);
|
|
|
|
bd.rq = rq;
|
|
|
|
/*
|
|
* Flag last if we have no more requests, or if we have more
|
|
* but can't assign a driver tag to it.
|
|
*/
|
|
if (list_empty(list))
|
|
bd.last = true;
|
|
else {
|
|
nxt = list_first_entry(list, struct request, queuelist);
|
|
bd.last = !blk_mq_get_driver_tag(nxt);
|
|
}
|
|
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
|
|
/*
|
|
* If an I/O scheduler has been configured and we got a
|
|
* driver tag for the next request already, free it
|
|
* again.
|
|
*/
|
|
if (!list_empty(list)) {
|
|
nxt = list_first_entry(list, struct request, queuelist);
|
|
blk_mq_put_driver_tag(nxt);
|
|
}
|
|
list_add(&rq->queuelist, list);
|
|
__blk_mq_requeue_request(rq);
|
|
break;
|
|
}
|
|
|
|
if (unlikely(ret != BLK_STS_OK)) {
|
|
errors++;
|
|
blk_mq_end_request(rq, BLK_STS_IOERR);
|
|
continue;
|
|
}
|
|
|
|
queued++;
|
|
} while (!list_empty(list));
|
|
|
|
hctx->dispatched[queued_to_index(queued)]++;
|
|
|
|
/*
|
|
* Any items that need requeuing? Stuff them into hctx->dispatch,
|
|
* that is where we will continue on next queue run.
|
|
*/
|
|
if (!list_empty(list)) {
|
|
bool needs_restart;
|
|
|
|
/*
|
|
* If we didn't flush the entire list, we could have told
|
|
* the driver there was more coming, but that turned out to
|
|
* be a lie.
|
|
*/
|
|
if (q->mq_ops->commit_rqs)
|
|
q->mq_ops->commit_rqs(hctx);
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_splice_init(list, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
/*
|
|
* If SCHED_RESTART was set by the caller of this function and
|
|
* it is no longer set that means that it was cleared by another
|
|
* thread and hence that a queue rerun is needed.
|
|
*
|
|
* If 'no_tag' is set, that means that we failed getting
|
|
* a driver tag with an I/O scheduler attached. If our dispatch
|
|
* waitqueue is no longer active, ensure that we run the queue
|
|
* AFTER adding our entries back to the list.
|
|
*
|
|
* If no I/O scheduler has been configured it is possible that
|
|
* the hardware queue got stopped and restarted before requests
|
|
* were pushed back onto the dispatch list. Rerun the queue to
|
|
* avoid starvation. Notes:
|
|
* - blk_mq_run_hw_queue() checks whether or not a queue has
|
|
* been stopped before rerunning a queue.
|
|
* - Some but not all block drivers stop a queue before
|
|
* returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
|
|
* and dm-rq.
|
|
*
|
|
* If driver returns BLK_STS_RESOURCE and SCHED_RESTART
|
|
* bit is set, run queue after a delay to avoid IO stalls
|
|
* that could otherwise occur if the queue is idle.
|
|
*/
|
|
needs_restart = blk_mq_sched_needs_restart(hctx);
|
|
if (!needs_restart ||
|
|
(no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
else if (needs_restart && (ret == BLK_STS_RESOURCE))
|
|
blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
|
|
|
|
blk_mq_update_dispatch_busy(hctx, true);
|
|
return false;
|
|
} else
|
|
blk_mq_update_dispatch_busy(hctx, false);
|
|
|
|
/*
|
|
* If the host/device is unable to accept more work, inform the
|
|
* caller of that.
|
|
*/
|
|
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
|
|
return false;
|
|
|
|
return (queued + errors) != 0;
|
|
}
|
|
|
|
static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
int srcu_idx;
|
|
|
|
/*
|
|
* We should be running this queue from one of the CPUs that
|
|
* are mapped to it.
|
|
*
|
|
* There are at least two related races now between setting
|
|
* hctx->next_cpu from blk_mq_hctx_next_cpu() and running
|
|
* __blk_mq_run_hw_queue():
|
|
*
|
|
* - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(),
|
|
* but later it becomes online, then this warning is harmless
|
|
* at all
|
|
*
|
|
* - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(),
|
|
* but later it becomes offline, then the warning can't be
|
|
* triggered, and we depend on blk-mq timeout handler to
|
|
* handle dispatched requests to this hctx
|
|
*/
|
|
if (!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
|
|
cpu_online(hctx->next_cpu)) {
|
|
printk(KERN_WARNING "run queue from wrong CPU %d, hctx %s\n",
|
|
raw_smp_processor_id(),
|
|
cpumask_empty(hctx->cpumask) ? "inactive": "active");
|
|
dump_stack();
|
|
}
|
|
|
|
/*
|
|
* We can't run the queue inline with ints disabled. Ensure that
|
|
* we catch bad users of this early.
|
|
*/
|
|
WARN_ON_ONCE(in_interrupt());
|
|
|
|
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
|
|
|
|
hctx_lock(hctx, &srcu_idx);
|
|
blk_mq_sched_dispatch_requests(hctx);
|
|
hctx_unlock(hctx, srcu_idx);
|
|
}
|
|
|
|
static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
|
|
|
|
if (cpu >= nr_cpu_ids)
|
|
cpu = cpumask_first(hctx->cpumask);
|
|
return cpu;
|
|
}
|
|
|
|
/*
|
|
* It'd be great if the workqueue API had a way to pass
|
|
* in a mask and had some smarts for more clever placement.
|
|
* For now we just round-robin here, switching for every
|
|
* BLK_MQ_CPU_WORK_BATCH queued items.
|
|
*/
|
|
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
bool tried = false;
|
|
int next_cpu = hctx->next_cpu;
|
|
|
|
if (hctx->queue->nr_hw_queues == 1)
|
|
return WORK_CPU_UNBOUND;
|
|
|
|
if (--hctx->next_cpu_batch <= 0) {
|
|
select_cpu:
|
|
next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
|
|
cpu_online_mask);
|
|
if (next_cpu >= nr_cpu_ids)
|
|
next_cpu = blk_mq_first_mapped_cpu(hctx);
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
|
|
/*
|
|
* Do unbound schedule if we can't find a online CPU for this hctx,
|
|
* and it should only happen in the path of handling CPU DEAD.
|
|
*/
|
|
if (!cpu_online(next_cpu)) {
|
|
if (!tried) {
|
|
tried = true;
|
|
goto select_cpu;
|
|
}
|
|
|
|
/*
|
|
* Make sure to re-select CPU next time once after CPUs
|
|
* in hctx->cpumask become online again.
|
|
*/
|
|
hctx->next_cpu = next_cpu;
|
|
hctx->next_cpu_batch = 1;
|
|
return WORK_CPU_UNBOUND;
|
|
}
|
|
|
|
hctx->next_cpu = next_cpu;
|
|
return next_cpu;
|
|
}
|
|
|
|
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
|
|
unsigned long msecs)
|
|
{
|
|
if (unlikely(blk_mq_hctx_stopped(hctx)))
|
|
return;
|
|
|
|
if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
int cpu = get_cpu();
|
|
if (cpumask_test_cpu(cpu, hctx->cpumask)) {
|
|
__blk_mq_run_hw_queue(hctx);
|
|
put_cpu();
|
|
return;
|
|
}
|
|
|
|
put_cpu();
|
|
}
|
|
|
|
kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
|
|
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
|
|
{
|
|
__blk_mq_delay_run_hw_queue(hctx, true, msecs);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
|
|
|
|
bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
|
|
{
|
|
int srcu_idx;
|
|
bool need_run;
|
|
|
|
/*
|
|
* When queue is quiesced, we may be switching io scheduler, or
|
|
* updating nr_hw_queues, or other things, and we can't run queue
|
|
* any more, even __blk_mq_hctx_has_pending() can't be called safely.
|
|
*
|
|
* And queue will be rerun in blk_mq_unquiesce_queue() if it is
|
|
* quiesced.
|
|
*/
|
|
hctx_lock(hctx, &srcu_idx);
|
|
need_run = !blk_queue_quiesced(hctx->queue) &&
|
|
blk_mq_hctx_has_pending(hctx);
|
|
hctx_unlock(hctx, srcu_idx);
|
|
|
|
if (need_run) {
|
|
__blk_mq_delay_run_hw_queue(hctx, async, 0);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_run_hw_queue);
|
|
|
|
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (blk_mq_hctx_stopped(hctx))
|
|
continue;
|
|
|
|
blk_mq_run_hw_queue(hctx, async);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_run_hw_queues);
|
|
|
|
/**
|
|
* blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
|
|
* @q: request queue.
|
|
*
|
|
* The caller is responsible for serializing this function against
|
|
* blk_mq_{start,stop}_hw_queue().
|
|
*/
|
|
bool blk_mq_queue_stopped(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
if (blk_mq_hctx_stopped(hctx))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_queue_stopped);
|
|
|
|
/*
|
|
* This function is often used for pausing .queue_rq() by driver when
|
|
* there isn't enough resource or some conditions aren't satisfied, and
|
|
* BLK_STS_RESOURCE is usually returned.
|
|
*
|
|
* We do not guarantee that dispatch can be drained or blocked
|
|
* after blk_mq_stop_hw_queue() returns. Please use
|
|
* blk_mq_quiesce_queue() for that requirement.
|
|
*/
|
|
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cancel_delayed_work(&hctx->run_work);
|
|
|
|
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
|
|
|
|
/*
|
|
* This function is often used for pausing .queue_rq() by driver when
|
|
* there isn't enough resource or some conditions aren't satisfied, and
|
|
* BLK_STS_RESOURCE is usually returned.
|
|
*
|
|
* We do not guarantee that dispatch can be drained or blocked
|
|
* after blk_mq_stop_hw_queues() returns. Please use
|
|
* blk_mq_quiesce_queue() for that requirement.
|
|
*/
|
|
void blk_mq_stop_hw_queues(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_stop_hw_queue(hctx);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_stop_hw_queues);
|
|
|
|
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
|
|
blk_mq_run_hw_queue(hctx, false);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_hw_queue);
|
|
|
|
void blk_mq_start_hw_queues(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_start_hw_queue(hctx);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_hw_queues);
|
|
|
|
void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
|
|
{
|
|
if (!blk_mq_hctx_stopped(hctx))
|
|
return;
|
|
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
blk_mq_run_hw_queue(hctx, async);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
|
|
|
|
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_start_stopped_hw_queue(hctx, async);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
|
|
|
|
static void blk_mq_run_work_fn(struct work_struct *work)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
|
|
|
|
/*
|
|
* If we are stopped, don't run the queue.
|
|
*/
|
|
if (test_bit(BLK_MQ_S_STOPPED, &hctx->state))
|
|
return;
|
|
|
|
__blk_mq_run_hw_queue(hctx);
|
|
}
|
|
|
|
static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
enum hctx_type type = hctx->type;
|
|
|
|
lockdep_assert_held(&ctx->lock);
|
|
|
|
trace_block_rq_insert(hctx->queue, rq);
|
|
|
|
if (at_head)
|
|
list_add(&rq->queuelist, &ctx->rq_lists[type]);
|
|
else
|
|
list_add_tail(&rq->queuelist, &ctx->rq_lists[type]);
|
|
}
|
|
|
|
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
|
|
lockdep_assert_held(&ctx->lock);
|
|
|
|
__blk_mq_insert_req_list(hctx, rq, at_head);
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
}
|
|
|
|
/*
|
|
* Should only be used carefully, when the caller knows we want to
|
|
* bypass a potential IO scheduler on the target device.
|
|
*/
|
|
void blk_mq_request_bypass_insert(struct request *rq, bool run_queue)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_add_tail(&rq->queuelist, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
if (run_queue)
|
|
blk_mq_run_hw_queue(hctx, false);
|
|
}
|
|
|
|
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
|
|
struct list_head *list)
|
|
|
|
{
|
|
struct request *rq;
|
|
enum hctx_type type = hctx->type;
|
|
|
|
/*
|
|
* preemption doesn't flush plug list, so it's possible ctx->cpu is
|
|
* offline now
|
|
*/
|
|
list_for_each_entry(rq, list, queuelist) {
|
|
BUG_ON(rq->mq_ctx != ctx);
|
|
trace_block_rq_insert(hctx->queue, rq);
|
|
}
|
|
|
|
spin_lock(&ctx->lock);
|
|
list_splice_tail_init(list, &ctx->rq_lists[type]);
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
|
|
{
|
|
struct request *rqa = container_of(a, struct request, queuelist);
|
|
struct request *rqb = container_of(b, struct request, queuelist);
|
|
|
|
if (rqa->mq_ctx < rqb->mq_ctx)
|
|
return -1;
|
|
else if (rqa->mq_ctx > rqb->mq_ctx)
|
|
return 1;
|
|
else if (rqa->mq_hctx < rqb->mq_hctx)
|
|
return -1;
|
|
else if (rqa->mq_hctx > rqb->mq_hctx)
|
|
return 1;
|
|
|
|
return blk_rq_pos(rqa) > blk_rq_pos(rqb);
|
|
}
|
|
|
|
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
struct blk_mq_hw_ctx *this_hctx;
|
|
struct blk_mq_ctx *this_ctx;
|
|
struct request_queue *this_q;
|
|
struct request *rq;
|
|
LIST_HEAD(list);
|
|
LIST_HEAD(rq_list);
|
|
unsigned int depth;
|
|
|
|
list_splice_init(&plug->mq_list, &list);
|
|
|
|
if (plug->rq_count > 2 && plug->multiple_queues)
|
|
list_sort(NULL, &list, plug_rq_cmp);
|
|
|
|
plug->rq_count = 0;
|
|
|
|
this_q = NULL;
|
|
this_hctx = NULL;
|
|
this_ctx = NULL;
|
|
depth = 0;
|
|
|
|
while (!list_empty(&list)) {
|
|
rq = list_entry_rq(list.next);
|
|
list_del_init(&rq->queuelist);
|
|
BUG_ON(!rq->q);
|
|
if (rq->mq_hctx != this_hctx || rq->mq_ctx != this_ctx) {
|
|
if (this_hctx) {
|
|
trace_block_unplug(this_q, depth, !from_schedule);
|
|
blk_mq_sched_insert_requests(this_hctx, this_ctx,
|
|
&rq_list,
|
|
from_schedule);
|
|
}
|
|
|
|
this_q = rq->q;
|
|
this_ctx = rq->mq_ctx;
|
|
this_hctx = rq->mq_hctx;
|
|
depth = 0;
|
|
}
|
|
|
|
depth++;
|
|
list_add_tail(&rq->queuelist, &rq_list);
|
|
}
|
|
|
|
/*
|
|
* If 'this_hctx' is set, we know we have entries to complete
|
|
* on 'rq_list'. Do those.
|
|
*/
|
|
if (this_hctx) {
|
|
trace_block_unplug(this_q, depth, !from_schedule);
|
|
blk_mq_sched_insert_requests(this_hctx, this_ctx, &rq_list,
|
|
from_schedule);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
|
|
unsigned int nr_segs)
|
|
{
|
|
if (bio->bi_opf & REQ_RAHEAD)
|
|
rq->cmd_flags |= REQ_FAILFAST_MASK;
|
|
|
|
rq->__sector = bio->bi_iter.bi_sector;
|
|
rq->write_hint = bio->bi_write_hint;
|
|
blk_rq_bio_prep(rq, bio, nr_segs);
|
|
|
|
blk_account_io_start(rq, true);
|
|
}
|
|
|
|
static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
blk_qc_t *cookie, bool last)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct blk_mq_queue_data bd = {
|
|
.rq = rq,
|
|
.last = last,
|
|
};
|
|
blk_qc_t new_cookie;
|
|
blk_status_t ret;
|
|
|
|
new_cookie = request_to_qc_t(hctx, rq);
|
|
|
|
/*
|
|
* For OK queue, we are done. For error, caller may kill it.
|
|
* Any other error (busy), just add it to our list as we
|
|
* previously would have done.
|
|
*/
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
switch (ret) {
|
|
case BLK_STS_OK:
|
|
blk_mq_update_dispatch_busy(hctx, false);
|
|
*cookie = new_cookie;
|
|
break;
|
|
case BLK_STS_RESOURCE:
|
|
case BLK_STS_DEV_RESOURCE:
|
|
blk_mq_update_dispatch_busy(hctx, true);
|
|
__blk_mq_requeue_request(rq);
|
|
break;
|
|
default:
|
|
blk_mq_update_dispatch_busy(hctx, false);
|
|
*cookie = BLK_QC_T_NONE;
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
blk_qc_t *cookie,
|
|
bool bypass_insert, bool last)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
bool run_queue = true;
|
|
|
|
/*
|
|
* RCU or SRCU read lock is needed before checking quiesced flag.
|
|
*
|
|
* When queue is stopped or quiesced, ignore 'bypass_insert' from
|
|
* blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
|
|
* and avoid driver to try to dispatch again.
|
|
*/
|
|
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
|
|
run_queue = false;
|
|
bypass_insert = false;
|
|
goto insert;
|
|
}
|
|
|
|
if (q->elevator && !bypass_insert)
|
|
goto insert;
|
|
|
|
if (!blk_mq_get_dispatch_budget(hctx))
|
|
goto insert;
|
|
|
|
if (!blk_mq_get_driver_tag(rq)) {
|
|
blk_mq_put_dispatch_budget(hctx);
|
|
goto insert;
|
|
}
|
|
|
|
return __blk_mq_issue_directly(hctx, rq, cookie, last);
|
|
insert:
|
|
if (bypass_insert)
|
|
return BLK_STS_RESOURCE;
|
|
|
|
blk_mq_request_bypass_insert(rq, run_queue);
|
|
return BLK_STS_OK;
|
|
}
|
|
|
|
static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, blk_qc_t *cookie)
|
|
{
|
|
blk_status_t ret;
|
|
int srcu_idx;
|
|
|
|
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
|
|
|
|
hctx_lock(hctx, &srcu_idx);
|
|
|
|
ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true);
|
|
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
|
|
blk_mq_request_bypass_insert(rq, true);
|
|
else if (ret != BLK_STS_OK)
|
|
blk_mq_end_request(rq, ret);
|
|
|
|
hctx_unlock(hctx, srcu_idx);
|
|
}
|
|
|
|
blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
|
|
{
|
|
blk_status_t ret;
|
|
int srcu_idx;
|
|
blk_qc_t unused_cookie;
|
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
|
|
|
|
hctx_lock(hctx, &srcu_idx);
|
|
ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last);
|
|
hctx_unlock(hctx, srcu_idx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
|
|
struct list_head *list)
|
|
{
|
|
while (!list_empty(list)) {
|
|
blk_status_t ret;
|
|
struct request *rq = list_first_entry(list, struct request,
|
|
queuelist);
|
|
|
|
list_del_init(&rq->queuelist);
|
|
ret = blk_mq_request_issue_directly(rq, list_empty(list));
|
|
if (ret != BLK_STS_OK) {
|
|
if (ret == BLK_STS_RESOURCE ||
|
|
ret == BLK_STS_DEV_RESOURCE) {
|
|
blk_mq_request_bypass_insert(rq,
|
|
list_empty(list));
|
|
break;
|
|
}
|
|
blk_mq_end_request(rq, ret);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we didn't flush the entire list, we could have told
|
|
* the driver there was more coming, but that turned out to
|
|
* be a lie.
|
|
*/
|
|
if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs)
|
|
hctx->queue->mq_ops->commit_rqs(hctx);
|
|
}
|
|
|
|
static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
|
|
{
|
|
list_add_tail(&rq->queuelist, &plug->mq_list);
|
|
plug->rq_count++;
|
|
if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) {
|
|
struct request *tmp;
|
|
|
|
tmp = list_first_entry(&plug->mq_list, struct request,
|
|
queuelist);
|
|
if (tmp->q != rq->q)
|
|
plug->multiple_queues = true;
|
|
}
|
|
}
|
|
|
|
static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
const int is_sync = op_is_sync(bio->bi_opf);
|
|
const int is_flush_fua = op_is_flush(bio->bi_opf);
|
|
struct blk_mq_alloc_data data = { .flags = 0};
|
|
struct request *rq;
|
|
struct blk_plug *plug;
|
|
struct request *same_queue_rq = NULL;
|
|
unsigned int nr_segs;
|
|
blk_qc_t cookie;
|
|
|
|
blk_queue_bounce(q, &bio);
|
|
__blk_queue_split(q, &bio, &nr_segs);
|
|
|
|
if (!bio_integrity_prep(bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (!is_flush_fua && !blk_queue_nomerges(q) &&
|
|
blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (blk_mq_sched_bio_merge(q, bio, nr_segs))
|
|
return BLK_QC_T_NONE;
|
|
|
|
rq_qos_throttle(q, bio);
|
|
|
|
data.cmd_flags = bio->bi_opf;
|
|
rq = blk_mq_get_request(q, bio, &data);
|
|
if (unlikely(!rq)) {
|
|
rq_qos_cleanup(q, bio);
|
|
if (bio->bi_opf & REQ_NOWAIT)
|
|
bio_wouldblock_error(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
trace_block_getrq(q, bio, bio->bi_opf);
|
|
|
|
rq_qos_track(q, rq, bio);
|
|
|
|
cookie = request_to_qc_t(data.hctx, rq);
|
|
|
|
blk_mq_bio_to_request(rq, bio, nr_segs);
|
|
|
|
plug = blk_mq_plug(q, bio);
|
|
if (unlikely(is_flush_fua)) {
|
|
/* bypass scheduler for flush rq */
|
|
blk_insert_flush(rq);
|
|
blk_mq_run_hw_queue(data.hctx, true);
|
|
} else if (plug && (q->nr_hw_queues == 1 || q->mq_ops->commit_rqs ||
|
|
!blk_queue_nonrot(q))) {
|
|
/*
|
|
* Use plugging if we have a ->commit_rqs() hook as well, as
|
|
* we know the driver uses bd->last in a smart fashion.
|
|
*
|
|
* Use normal plugging if this disk is slow HDD, as sequential
|
|
* IO may benefit a lot from plug merging.
|
|
*/
|
|
unsigned int request_count = plug->rq_count;
|
|
struct request *last = NULL;
|
|
|
|
if (!request_count)
|
|
trace_block_plug(q);
|
|
else
|
|
last = list_entry_rq(plug->mq_list.prev);
|
|
|
|
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
|
|
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
|
|
blk_flush_plug_list(plug, false);
|
|
trace_block_plug(q);
|
|
}
|
|
|
|
blk_add_rq_to_plug(plug, rq);
|
|
} else if (q->elevator) {
|
|
blk_mq_sched_insert_request(rq, false, true, true);
|
|
} else if (plug && !blk_queue_nomerges(q)) {
|
|
/*
|
|
* We do limited plugging. If the bio can be merged, do that.
|
|
* Otherwise the existing request in the plug list will be
|
|
* issued. So the plug list will have one request at most
|
|
* The plug list might get flushed before this. If that happens,
|
|
* the plug list is empty, and same_queue_rq is invalid.
|
|
*/
|
|
if (list_empty(&plug->mq_list))
|
|
same_queue_rq = NULL;
|
|
if (same_queue_rq) {
|
|
list_del_init(&same_queue_rq->queuelist);
|
|
plug->rq_count--;
|
|
}
|
|
blk_add_rq_to_plug(plug, rq);
|
|
trace_block_plug(q);
|
|
|
|
if (same_queue_rq) {
|
|
data.hctx = same_queue_rq->mq_hctx;
|
|
trace_block_unplug(q, 1, true);
|
|
blk_mq_try_issue_directly(data.hctx, same_queue_rq,
|
|
&cookie);
|
|
}
|
|
} else if ((q->nr_hw_queues > 1 && is_sync) ||
|
|
!data.hctx->dispatch_busy) {
|
|
blk_mq_try_issue_directly(data.hctx, rq, &cookie);
|
|
} else {
|
|
blk_mq_sched_insert_request(rq, false, true, true);
|
|
}
|
|
|
|
return cookie;
|
|
}
|
|
|
|
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx)
|
|
{
|
|
struct page *page;
|
|
|
|
if (tags->rqs && set->ops->exit_request) {
|
|
int i;
|
|
|
|
for (i = 0; i < tags->nr_tags; i++) {
|
|
struct request *rq = tags->static_rqs[i];
|
|
|
|
if (!rq)
|
|
continue;
|
|
set->ops->exit_request(set, rq, hctx_idx);
|
|
tags->static_rqs[i] = NULL;
|
|
}
|
|
}
|
|
|
|
while (!list_empty(&tags->page_list)) {
|
|
page = list_first_entry(&tags->page_list, struct page, lru);
|
|
list_del_init(&page->lru);
|
|
/*
|
|
* Remove kmemleak object previously allocated in
|
|
* blk_mq_alloc_rqs().
|
|
*/
|
|
kmemleak_free(page_address(page));
|
|
__free_pages(page, page->private);
|
|
}
|
|
}
|
|
|
|
void blk_mq_free_rq_map(struct blk_mq_tags *tags)
|
|
{
|
|
kfree(tags->rqs);
|
|
tags->rqs = NULL;
|
|
kfree(tags->static_rqs);
|
|
tags->static_rqs = NULL;
|
|
|
|
blk_mq_free_tags(tags);
|
|
}
|
|
|
|
struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx,
|
|
unsigned int nr_tags,
|
|
unsigned int reserved_tags)
|
|
{
|
|
struct blk_mq_tags *tags;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
|
|
BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
|
|
if (!tags)
|
|
return NULL;
|
|
|
|
tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->rqs) {
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->static_rqs) {
|
|
kfree(tags->rqs);
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
return tags;
|
|
}
|
|
|
|
static size_t order_to_size(unsigned int order)
|
|
{
|
|
return (size_t)PAGE_SIZE << order;
|
|
}
|
|
|
|
static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
|
|
unsigned int hctx_idx, int node)
|
|
{
|
|
int ret;
|
|
|
|
if (set->ops->init_request) {
|
|
ret = set->ops->init_request(set, rq, hctx_idx, node);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
|
|
return 0;
|
|
}
|
|
|
|
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx, unsigned int depth)
|
|
{
|
|
unsigned int i, j, entries_per_page, max_order = 4;
|
|
size_t rq_size, left;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
INIT_LIST_HEAD(&tags->page_list);
|
|
|
|
/*
|
|
* rq_size is the size of the request plus driver payload, rounded
|
|
* to the cacheline size
|
|
*/
|
|
rq_size = round_up(sizeof(struct request) + set->cmd_size,
|
|
cache_line_size());
|
|
left = rq_size * depth;
|
|
|
|
for (i = 0; i < depth; ) {
|
|
int this_order = max_order;
|
|
struct page *page;
|
|
int to_do;
|
|
void *p;
|
|
|
|
while (this_order && left < order_to_size(this_order - 1))
|
|
this_order--;
|
|
|
|
do {
|
|
page = alloc_pages_node(node,
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
|
|
this_order);
|
|
if (page)
|
|
break;
|
|
if (!this_order--)
|
|
break;
|
|
if (order_to_size(this_order) < rq_size)
|
|
break;
|
|
} while (1);
|
|
|
|
if (!page)
|
|
goto fail;
|
|
|
|
page->private = this_order;
|
|
list_add_tail(&page->lru, &tags->page_list);
|
|
|
|
p = page_address(page);
|
|
/*
|
|
* Allow kmemleak to scan these pages as they contain pointers
|
|
* to additional allocations like via ops->init_request().
|
|
*/
|
|
kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
|
|
entries_per_page = order_to_size(this_order) / rq_size;
|
|
to_do = min(entries_per_page, depth - i);
|
|
left -= to_do * rq_size;
|
|
for (j = 0; j < to_do; j++) {
|
|
struct request *rq = p;
|
|
|
|
tags->static_rqs[i] = rq;
|
|
if (blk_mq_init_request(set, rq, hctx_idx, node)) {
|
|
tags->static_rqs[i] = NULL;
|
|
goto fail;
|
|
}
|
|
|
|
p += rq_size;
|
|
i++;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
fail:
|
|
blk_mq_free_rqs(set, tags, hctx_idx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* 'cpu' is going away. splice any existing rq_list entries from this
|
|
* software queue to the hw queue dispatch list, and ensure that it
|
|
* gets run.
|
|
*/
|
|
static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
LIST_HEAD(tmp);
|
|
enum hctx_type type;
|
|
|
|
hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
|
|
ctx = __blk_mq_get_ctx(hctx->queue, cpu);
|
|
type = hctx->type;
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (!list_empty(&ctx->rq_lists[type])) {
|
|
list_splice_init(&ctx->rq_lists[type], &tmp);
|
|
blk_mq_hctx_clear_pending(hctx, ctx);
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
|
|
if (list_empty(&tmp))
|
|
return 0;
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_splice_tail_init(&tmp, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 0;
|
|
}
|
|
|
|
static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
|
|
&hctx->cpuhp_dead);
|
|
}
|
|
|
|
/* hctx->ctxs will be freed in queue's release handler */
|
|
static void blk_mq_exit_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
|
|
{
|
|
if (blk_mq_hw_queue_mapped(hctx))
|
|
blk_mq_tag_idle(hctx);
|
|
|
|
if (set->ops->exit_request)
|
|
set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
|
|
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
|
|
blk_mq_remove_cpuhp(hctx);
|
|
|
|
spin_lock(&q->unused_hctx_lock);
|
|
list_add(&hctx->hctx_list, &q->unused_hctx_list);
|
|
spin_unlock(&q->unused_hctx_lock);
|
|
}
|
|
|
|
static void blk_mq_exit_hw_queues(struct request_queue *q,
|
|
struct blk_mq_tag_set *set, int nr_queue)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (i == nr_queue)
|
|
break;
|
|
blk_mq_debugfs_unregister_hctx(hctx);
|
|
blk_mq_exit_hctx(q, set, hctx, i);
|
|
}
|
|
}
|
|
|
|
static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set)
|
|
{
|
|
int hw_ctx_size = sizeof(struct blk_mq_hw_ctx);
|
|
|
|
BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, srcu),
|
|
__alignof__(struct blk_mq_hw_ctx)) !=
|
|
sizeof(struct blk_mq_hw_ctx));
|
|
|
|
if (tag_set->flags & BLK_MQ_F_BLOCKING)
|
|
hw_ctx_size += sizeof(struct srcu_struct);
|
|
|
|
return hw_ctx_size;
|
|
}
|
|
|
|
static int blk_mq_init_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
|
|
{
|
|
hctx->queue_num = hctx_idx;
|
|
|
|
cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
|
|
|
|
hctx->tags = set->tags[hctx_idx];
|
|
|
|
if (set->ops->init_hctx &&
|
|
set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
|
|
goto unregister_cpu_notifier;
|
|
|
|
if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
|
|
hctx->numa_node))
|
|
goto exit_hctx;
|
|
return 0;
|
|
|
|
exit_hctx:
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
unregister_cpu_notifier:
|
|
blk_mq_remove_cpuhp(hctx);
|
|
return -1;
|
|
}
|
|
|
|
static struct blk_mq_hw_ctx *
|
|
blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
|
|
int node)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
|
|
|
|
hctx = kzalloc_node(blk_mq_hw_ctx_size(set), gfp, node);
|
|
if (!hctx)
|
|
goto fail_alloc_hctx;
|
|
|
|
if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
|
|
goto free_hctx;
|
|
|
|
atomic_set(&hctx->nr_active, 0);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
hctx->numa_node = node;
|
|
|
|
INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
|
|
spin_lock_init(&hctx->lock);
|
|
INIT_LIST_HEAD(&hctx->dispatch);
|
|
hctx->queue = q;
|
|
hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
|
|
|
|
INIT_LIST_HEAD(&hctx->hctx_list);
|
|
|
|
/*
|
|
* Allocate space for all possible cpus to avoid allocation at
|
|
* runtime
|
|
*/
|
|
hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
|
|
gfp, node);
|
|
if (!hctx->ctxs)
|
|
goto free_cpumask;
|
|
|
|
if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
|
|
gfp, node))
|
|
goto free_ctxs;
|
|
hctx->nr_ctx = 0;
|
|
|
|
spin_lock_init(&hctx->dispatch_wait_lock);
|
|
init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
|
|
INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
|
|
|
|
hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size,
|
|
gfp);
|
|
if (!hctx->fq)
|
|
goto free_bitmap;
|
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
init_srcu_struct(hctx->srcu);
|
|
blk_mq_hctx_kobj_init(hctx);
|
|
|
|
return hctx;
|
|
|
|
free_bitmap:
|
|
sbitmap_free(&hctx->ctx_map);
|
|
free_ctxs:
|
|
kfree(hctx->ctxs);
|
|
free_cpumask:
|
|
free_cpumask_var(hctx->cpumask);
|
|
free_hctx:
|
|
kfree(hctx);
|
|
fail_alloc_hctx:
|
|
return NULL;
|
|
}
|
|
|
|
static void blk_mq_init_cpu_queues(struct request_queue *q,
|
|
unsigned int nr_hw_queues)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
unsigned int i, j;
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int k;
|
|
|
|
__ctx->cpu = i;
|
|
spin_lock_init(&__ctx->lock);
|
|
for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
|
|
INIT_LIST_HEAD(&__ctx->rq_lists[k]);
|
|
|
|
__ctx->queue = q;
|
|
|
|
/*
|
|
* Set local node, IFF we have more than one hw queue. If
|
|
* not, we remain on the home node of the device
|
|
*/
|
|
for (j = 0; j < set->nr_maps; j++) {
|
|
hctx = blk_mq_map_queue_type(q, j, i);
|
|
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
|
|
hctx->numa_node = local_memory_node(cpu_to_node(i));
|
|
}
|
|
}
|
|
}
|
|
|
|
static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx)
|
|
{
|
|
int ret = 0;
|
|
|
|
set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
|
|
set->queue_depth, set->reserved_tags);
|
|
if (!set->tags[hctx_idx])
|
|
return false;
|
|
|
|
ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
|
|
set->queue_depth);
|
|
if (!ret)
|
|
return true;
|
|
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
return false;
|
|
}
|
|
|
|
static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx)
|
|
{
|
|
if (set->tags && set->tags[hctx_idx]) {
|
|
blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx);
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_map_swqueue(struct request_queue *q)
|
|
{
|
|
unsigned int i, j, hctx_idx;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
cpumask_clear(hctx->cpumask);
|
|
hctx->nr_ctx = 0;
|
|
hctx->dispatch_from = NULL;
|
|
}
|
|
|
|
/*
|
|
* Map software to hardware queues.
|
|
*
|
|
* If the cpu isn't present, the cpu is mapped to first hctx.
|
|
*/
|
|
for_each_possible_cpu(i) {
|
|
hctx_idx = set->map[HCTX_TYPE_DEFAULT].mq_map[i];
|
|
/* unmapped hw queue can be remapped after CPU topo changed */
|
|
if (!set->tags[hctx_idx] &&
|
|
!__blk_mq_alloc_rq_map(set, hctx_idx)) {
|
|
/*
|
|
* If tags initialization fail for some hctx,
|
|
* that hctx won't be brought online. In this
|
|
* case, remap the current ctx to hctx[0] which
|
|
* is guaranteed to always have tags allocated
|
|
*/
|
|
set->map[HCTX_TYPE_DEFAULT].mq_map[i] = 0;
|
|
}
|
|
|
|
ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
for (j = 0; j < set->nr_maps; j++) {
|
|
if (!set->map[j].nr_queues) {
|
|
ctx->hctxs[j] = blk_mq_map_queue_type(q,
|
|
HCTX_TYPE_DEFAULT, i);
|
|
continue;
|
|
}
|
|
|
|
hctx = blk_mq_map_queue_type(q, j, i);
|
|
ctx->hctxs[j] = hctx;
|
|
/*
|
|
* If the CPU is already set in the mask, then we've
|
|
* mapped this one already. This can happen if
|
|
* devices share queues across queue maps.
|
|
*/
|
|
if (cpumask_test_cpu(i, hctx->cpumask))
|
|
continue;
|
|
|
|
cpumask_set_cpu(i, hctx->cpumask);
|
|
hctx->type = j;
|
|
ctx->index_hw[hctx->type] = hctx->nr_ctx;
|
|
hctx->ctxs[hctx->nr_ctx++] = ctx;
|
|
|
|
/*
|
|
* If the nr_ctx type overflows, we have exceeded the
|
|
* amount of sw queues we can support.
|
|
*/
|
|
BUG_ON(!hctx->nr_ctx);
|
|
}
|
|
|
|
for (; j < HCTX_MAX_TYPES; j++)
|
|
ctx->hctxs[j] = blk_mq_map_queue_type(q,
|
|
HCTX_TYPE_DEFAULT, i);
|
|
}
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/*
|
|
* If no software queues are mapped to this hardware queue,
|
|
* disable it and free the request entries.
|
|
*/
|
|
if (!hctx->nr_ctx) {
|
|
/* Never unmap queue 0. We need it as a
|
|
* fallback in case of a new remap fails
|
|
* allocation
|
|
*/
|
|
if (i && set->tags[i])
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
hctx->tags = NULL;
|
|
continue;
|
|
}
|
|
|
|
hctx->tags = set->tags[i];
|
|
WARN_ON(!hctx->tags);
|
|
|
|
/*
|
|
* Set the map size to the number of mapped software queues.
|
|
* This is more accurate and more efficient than looping
|
|
* over all possibly mapped software queues.
|
|
*/
|
|
sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
|
|
|
|
/*
|
|
* Initialize batch roundrobin counts
|
|
*/
|
|
hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Caller needs to ensure that we're either frozen/quiesced, or that
|
|
* the queue isn't live yet.
|
|
*/
|
|
static void queue_set_hctx_shared(struct request_queue *q, bool shared)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (shared)
|
|
hctx->flags |= BLK_MQ_F_TAG_SHARED;
|
|
else
|
|
hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set,
|
|
bool shared)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
lockdep_assert_held(&set->tag_list_lock);
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_freeze_queue(q);
|
|
queue_set_hctx_shared(q, shared);
|
|
blk_mq_unfreeze_queue(q);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_del_queue_tag_set(struct request_queue *q)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
mutex_lock(&set->tag_list_lock);
|
|
list_del_rcu(&q->tag_set_list);
|
|
if (list_is_singular(&set->tag_list)) {
|
|
/* just transitioned to unshared */
|
|
set->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, false);
|
|
}
|
|
mutex_unlock(&set->tag_list_lock);
|
|
INIT_LIST_HEAD(&q->tag_set_list);
|
|
}
|
|
|
|
static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
mutex_lock(&set->tag_list_lock);
|
|
|
|
/*
|
|
* Check to see if we're transitioning to shared (from 1 to 2 queues).
|
|
*/
|
|
if (!list_empty(&set->tag_list) &&
|
|
!(set->flags & BLK_MQ_F_TAG_SHARED)) {
|
|
set->flags |= BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, true);
|
|
}
|
|
if (set->flags & BLK_MQ_F_TAG_SHARED)
|
|
queue_set_hctx_shared(q, true);
|
|
list_add_tail_rcu(&q->tag_set_list, &set->tag_list);
|
|
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
|
|
/* All allocations will be freed in release handler of q->mq_kobj */
|
|
static int blk_mq_alloc_ctxs(struct request_queue *q)
|
|
{
|
|
struct blk_mq_ctxs *ctxs;
|
|
int cpu;
|
|
|
|
ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
|
|
if (!ctxs)
|
|
return -ENOMEM;
|
|
|
|
ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
|
|
if (!ctxs->queue_ctx)
|
|
goto fail;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
|
|
ctx->ctxs = ctxs;
|
|
}
|
|
|
|
q->mq_kobj = &ctxs->kobj;
|
|
q->queue_ctx = ctxs->queue_ctx;
|
|
|
|
return 0;
|
|
fail:
|
|
kfree(ctxs);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* It is the actual release handler for mq, but we do it from
|
|
* request queue's release handler for avoiding use-after-free
|
|
* and headache because q->mq_kobj shouldn't have been introduced,
|
|
* but we can't group ctx/kctx kobj without it.
|
|
*/
|
|
void blk_mq_release(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx, *next;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
|
|
|
|
/* all hctx are in .unused_hctx_list now */
|
|
list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
|
|
list_del_init(&hctx->hctx_list);
|
|
kobject_put(&hctx->kobj);
|
|
}
|
|
|
|
kfree(q->queue_hw_ctx);
|
|
|
|
/*
|
|
* release .mq_kobj and sw queue's kobject now because
|
|
* both share lifetime with request queue.
|
|
*/
|
|
blk_mq_sysfs_deinit(q);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
|
|
{
|
|
struct request_queue *uninit_q, *q;
|
|
|
|
uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node);
|
|
if (!uninit_q)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/*
|
|
* Initialize the queue without an elevator. device_add_disk() will do
|
|
* the initialization.
|
|
*/
|
|
q = blk_mq_init_allocated_queue(set, uninit_q, false);
|
|
if (IS_ERR(q))
|
|
blk_cleanup_queue(uninit_q);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_queue);
|
|
|
|
/*
|
|
* Helper for setting up a queue with mq ops, given queue depth, and
|
|
* the passed in mq ops flags.
|
|
*/
|
|
struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
|
|
const struct blk_mq_ops *ops,
|
|
unsigned int queue_depth,
|
|
unsigned int set_flags)
|
|
{
|
|
struct request_queue *q;
|
|
int ret;
|
|
|
|
memset(set, 0, sizeof(*set));
|
|
set->ops = ops;
|
|
set->nr_hw_queues = 1;
|
|
set->nr_maps = 1;
|
|
set->queue_depth = queue_depth;
|
|
set->numa_node = NUMA_NO_NODE;
|
|
set->flags = set_flags;
|
|
|
|
ret = blk_mq_alloc_tag_set(set);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
q = blk_mq_init_queue(set);
|
|
if (IS_ERR(q)) {
|
|
blk_mq_free_tag_set(set);
|
|
return q;
|
|
}
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_sq_queue);
|
|
|
|
static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
|
|
struct blk_mq_tag_set *set, struct request_queue *q,
|
|
int hctx_idx, int node)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx = NULL, *tmp;
|
|
|
|
/* reuse dead hctx first */
|
|
spin_lock(&q->unused_hctx_lock);
|
|
list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
|
|
if (tmp->numa_node == node) {
|
|
hctx = tmp;
|
|
break;
|
|
}
|
|
}
|
|
if (hctx)
|
|
list_del_init(&hctx->hctx_list);
|
|
spin_unlock(&q->unused_hctx_lock);
|
|
|
|
if (!hctx)
|
|
hctx = blk_mq_alloc_hctx(q, set, node);
|
|
if (!hctx)
|
|
goto fail;
|
|
|
|
if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
|
|
goto free_hctx;
|
|
|
|
return hctx;
|
|
|
|
free_hctx:
|
|
kobject_put(&hctx->kobj);
|
|
fail:
|
|
return NULL;
|
|
}
|
|
|
|
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
int i, j, end;
|
|
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
|
|
|
|
/* protect against switching io scheduler */
|
|
mutex_lock(&q->sysfs_lock);
|
|
for (i = 0; i < set->nr_hw_queues; i++) {
|
|
int node;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], i);
|
|
/*
|
|
* If the hw queue has been mapped to another numa node,
|
|
* we need to realloc the hctx. If allocation fails, fallback
|
|
* to use the previous one.
|
|
*/
|
|
if (hctxs[i] && (hctxs[i]->numa_node == node))
|
|
continue;
|
|
|
|
hctx = blk_mq_alloc_and_init_hctx(set, q, i, node);
|
|
if (hctx) {
|
|
if (hctxs[i])
|
|
blk_mq_exit_hctx(q, set, hctxs[i], i);
|
|
hctxs[i] = hctx;
|
|
} else {
|
|
if (hctxs[i])
|
|
pr_warn("Allocate new hctx on node %d fails,\
|
|
fallback to previous one on node %d\n",
|
|
node, hctxs[i]->numa_node);
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* Increasing nr_hw_queues fails. Free the newly allocated
|
|
* hctxs and keep the previous q->nr_hw_queues.
|
|
*/
|
|
if (i != set->nr_hw_queues) {
|
|
j = q->nr_hw_queues;
|
|
end = i;
|
|
} else {
|
|
j = i;
|
|
end = q->nr_hw_queues;
|
|
q->nr_hw_queues = set->nr_hw_queues;
|
|
}
|
|
|
|
for (; j < end; j++) {
|
|
struct blk_mq_hw_ctx *hctx = hctxs[j];
|
|
|
|
if (hctx) {
|
|
if (hctx->tags)
|
|
blk_mq_free_map_and_requests(set, j);
|
|
blk_mq_exit_hctx(q, set, hctx, j);
|
|
hctxs[j] = NULL;
|
|
}
|
|
}
|
|
mutex_unlock(&q->sysfs_lock);
|
|
}
|
|
|
|
/*
|
|
* Maximum number of hardware queues we support. For single sets, we'll never
|
|
* have more than the CPUs (software queues). For multiple sets, the tag_set
|
|
* user may have set ->nr_hw_queues larger.
|
|
*/
|
|
static unsigned int nr_hw_queues(struct blk_mq_tag_set *set)
|
|
{
|
|
if (set->nr_maps == 1)
|
|
return nr_cpu_ids;
|
|
|
|
return max(set->nr_hw_queues, nr_cpu_ids);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
|
|
struct request_queue *q,
|
|
bool elevator_init)
|
|
{
|
|
/* mark the queue as mq asap */
|
|
q->mq_ops = set->ops;
|
|
|
|
q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn,
|
|
blk_mq_poll_stats_bkt,
|
|
BLK_MQ_POLL_STATS_BKTS, q);
|
|
if (!q->poll_cb)
|
|
goto err_exit;
|
|
|
|
if (blk_mq_alloc_ctxs(q))
|
|
goto err_poll;
|
|
|
|
/* init q->mq_kobj and sw queues' kobjects */
|
|
blk_mq_sysfs_init(q);
|
|
|
|
q->nr_queues = nr_hw_queues(set);
|
|
q->queue_hw_ctx = kcalloc_node(q->nr_queues, sizeof(*(q->queue_hw_ctx)),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!q->queue_hw_ctx)
|
|
goto err_sys_init;
|
|
|
|
INIT_LIST_HEAD(&q->unused_hctx_list);
|
|
spin_lock_init(&q->unused_hctx_lock);
|
|
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
if (!q->nr_hw_queues)
|
|
goto err_hctxs;
|
|
|
|
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
|
|
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
|
|
|
|
q->tag_set = set;
|
|
|
|
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
|
|
if (set->nr_maps > HCTX_TYPE_POLL &&
|
|
set->map[HCTX_TYPE_POLL].nr_queues)
|
|
blk_queue_flag_set(QUEUE_FLAG_POLL, q);
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
|
|
INIT_LIST_HEAD(&q->requeue_list);
|
|
spin_lock_init(&q->requeue_lock);
|
|
|
|
blk_queue_make_request(q, blk_mq_make_request);
|
|
|
|
/*
|
|
* Do this after blk_queue_make_request() overrides it...
|
|
*/
|
|
q->nr_requests = set->queue_depth;
|
|
|
|
/*
|
|
* Default to classic polling
|
|
*/
|
|
q->poll_nsec = BLK_MQ_POLL_CLASSIC;
|
|
|
|
blk_mq_init_cpu_queues(q, set->nr_hw_queues);
|
|
blk_mq_add_queue_tag_set(set, q);
|
|
blk_mq_map_swqueue(q);
|
|
|
|
if (elevator_init)
|
|
elevator_init_mq(q);
|
|
|
|
return q;
|
|
|
|
err_hctxs:
|
|
kfree(q->queue_hw_ctx);
|
|
q->nr_hw_queues = 0;
|
|
err_sys_init:
|
|
blk_mq_sysfs_deinit(q);
|
|
err_poll:
|
|
blk_stat_free_callback(q->poll_cb);
|
|
q->poll_cb = NULL;
|
|
err_exit:
|
|
q->mq_ops = NULL;
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_allocated_queue);
|
|
|
|
/* tags can _not_ be used after returning from blk_mq_exit_queue */
|
|
void blk_mq_exit_queue(struct request_queue *q)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
blk_mq_del_queue_tag_set(q);
|
|
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
|
|
}
|
|
|
|
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < set->nr_hw_queues; i++)
|
|
if (!__blk_mq_alloc_rq_map(set, i))
|
|
goto out_unwind;
|
|
|
|
return 0;
|
|
|
|
out_unwind:
|
|
while (--i >= 0)
|
|
blk_mq_free_rq_map(set->tags[i]);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Allocate the request maps associated with this tag_set. Note that this
|
|
* may reduce the depth asked for, if memory is tight. set->queue_depth
|
|
* will be updated to reflect the allocated depth.
|
|
*/
|
|
static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
unsigned int depth;
|
|
int err;
|
|
|
|
depth = set->queue_depth;
|
|
do {
|
|
err = __blk_mq_alloc_rq_maps(set);
|
|
if (!err)
|
|
break;
|
|
|
|
set->queue_depth >>= 1;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
|
|
err = -ENOMEM;
|
|
break;
|
|
}
|
|
} while (set->queue_depth);
|
|
|
|
if (!set->queue_depth || err) {
|
|
pr_err("blk-mq: failed to allocate request map\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (depth != set->queue_depth)
|
|
pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
|
|
depth, set->queue_depth);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
|
|
{
|
|
if (set->ops->map_queues && !is_kdump_kernel()) {
|
|
int i;
|
|
|
|
/*
|
|
* transport .map_queues is usually done in the following
|
|
* way:
|
|
*
|
|
* for (queue = 0; queue < set->nr_hw_queues; queue++) {
|
|
* mask = get_cpu_mask(queue)
|
|
* for_each_cpu(cpu, mask)
|
|
* set->map[x].mq_map[cpu] = queue;
|
|
* }
|
|
*
|
|
* When we need to remap, the table has to be cleared for
|
|
* killing stale mapping since one CPU may not be mapped
|
|
* to any hw queue.
|
|
*/
|
|
for (i = 0; i < set->nr_maps; i++)
|
|
blk_mq_clear_mq_map(&set->map[i]);
|
|
|
|
return set->ops->map_queues(set);
|
|
} else {
|
|
BUG_ON(set->nr_maps > 1);
|
|
return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Alloc a tag set to be associated with one or more request queues.
|
|
* May fail with EINVAL for various error conditions. May adjust the
|
|
* requested depth down, if it's too large. In that case, the set
|
|
* value will be stored in set->queue_depth.
|
|
*/
|
|
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int i, ret;
|
|
|
|
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
|
|
|
|
if (!set->nr_hw_queues)
|
|
return -EINVAL;
|
|
if (!set->queue_depth)
|
|
return -EINVAL;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
|
|
return -EINVAL;
|
|
|
|
if (!set->ops->queue_rq)
|
|
return -EINVAL;
|
|
|
|
if (!set->ops->get_budget ^ !set->ops->put_budget)
|
|
return -EINVAL;
|
|
|
|
if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
|
|
pr_info("blk-mq: reduced tag depth to %u\n",
|
|
BLK_MQ_MAX_DEPTH);
|
|
set->queue_depth = BLK_MQ_MAX_DEPTH;
|
|
}
|
|
|
|
if (!set->nr_maps)
|
|
set->nr_maps = 1;
|
|
else if (set->nr_maps > HCTX_MAX_TYPES)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* If a crashdump is active, then we are potentially in a very
|
|
* memory constrained environment. Limit us to 1 queue and
|
|
* 64 tags to prevent using too much memory.
|
|
*/
|
|
if (is_kdump_kernel()) {
|
|
set->nr_hw_queues = 1;
|
|
set->nr_maps = 1;
|
|
set->queue_depth = min(64U, set->queue_depth);
|
|
}
|
|
/*
|
|
* There is no use for more h/w queues than cpus if we just have
|
|
* a single map
|
|
*/
|
|
if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
|
|
set->nr_hw_queues = nr_cpu_ids;
|
|
|
|
set->tags = kcalloc_node(nr_hw_queues(set), sizeof(struct blk_mq_tags *),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->tags)
|
|
return -ENOMEM;
|
|
|
|
ret = -ENOMEM;
|
|
for (i = 0; i < set->nr_maps; i++) {
|
|
set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
|
|
sizeof(set->map[i].mq_map[0]),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->map[i].mq_map)
|
|
goto out_free_mq_map;
|
|
set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
|
|
}
|
|
|
|
ret = blk_mq_update_queue_map(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
ret = blk_mq_alloc_rq_maps(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
mutex_init(&set->tag_list_lock);
|
|
INIT_LIST_HEAD(&set->tag_list);
|
|
|
|
return 0;
|
|
|
|
out_free_mq_map:
|
|
for (i = 0; i < set->nr_maps; i++) {
|
|
kfree(set->map[i].mq_map);
|
|
set->map[i].mq_map = NULL;
|
|
}
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_alloc_tag_set);
|
|
|
|
void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int i, j;
|
|
|
|
for (i = 0; i < nr_hw_queues(set); i++)
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
for (j = 0; j < set->nr_maps; j++) {
|
|
kfree(set->map[j].mq_map);
|
|
set->map[j].mq_map = NULL;
|
|
}
|
|
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_free_tag_set);
|
|
|
|
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i, ret;
|
|
|
|
if (!set)
|
|
return -EINVAL;
|
|
|
|
if (q->nr_requests == nr)
|
|
return 0;
|
|
|
|
blk_mq_freeze_queue(q);
|
|
blk_mq_quiesce_queue(q);
|
|
|
|
ret = 0;
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (!hctx->tags)
|
|
continue;
|
|
/*
|
|
* If we're using an MQ scheduler, just update the scheduler
|
|
* queue depth. This is similar to what the old code would do.
|
|
*/
|
|
if (!hctx->sched_tags) {
|
|
ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
|
|
false);
|
|
} else {
|
|
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
|
|
nr, true);
|
|
}
|
|
if (ret)
|
|
break;
|
|
if (q->elevator && q->elevator->type->ops.depth_updated)
|
|
q->elevator->type->ops.depth_updated(hctx);
|
|
}
|
|
|
|
if (!ret)
|
|
q->nr_requests = nr;
|
|
|
|
blk_mq_unquiesce_queue(q);
|
|
blk_mq_unfreeze_queue(q);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* request_queue and elevator_type pair.
|
|
* It is just used by __blk_mq_update_nr_hw_queues to cache
|
|
* the elevator_type associated with a request_queue.
|
|
*/
|
|
struct blk_mq_qe_pair {
|
|
struct list_head node;
|
|
struct request_queue *q;
|
|
struct elevator_type *type;
|
|
};
|
|
|
|
/*
|
|
* Cache the elevator_type in qe pair list and switch the
|
|
* io scheduler to 'none'
|
|
*/
|
|
static bool blk_mq_elv_switch_none(struct list_head *head,
|
|
struct request_queue *q)
|
|
{
|
|
struct blk_mq_qe_pair *qe;
|
|
|
|
if (!q->elevator)
|
|
return true;
|
|
|
|
qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
|
|
if (!qe)
|
|
return false;
|
|
|
|
INIT_LIST_HEAD(&qe->node);
|
|
qe->q = q;
|
|
qe->type = q->elevator->type;
|
|
list_add(&qe->node, head);
|
|
|
|
mutex_lock(&q->sysfs_lock);
|
|
/*
|
|
* After elevator_switch_mq, the previous elevator_queue will be
|
|
* released by elevator_release. The reference of the io scheduler
|
|
* module get by elevator_get will also be put. So we need to get
|
|
* a reference of the io scheduler module here to prevent it to be
|
|
* removed.
|
|
*/
|
|
__module_get(qe->type->elevator_owner);
|
|
elevator_switch_mq(q, NULL);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
return true;
|
|
}
|
|
|
|
static void blk_mq_elv_switch_back(struct list_head *head,
|
|
struct request_queue *q)
|
|
{
|
|
struct blk_mq_qe_pair *qe;
|
|
struct elevator_type *t = NULL;
|
|
|
|
list_for_each_entry(qe, head, node)
|
|
if (qe->q == q) {
|
|
t = qe->type;
|
|
break;
|
|
}
|
|
|
|
if (!t)
|
|
return;
|
|
|
|
list_del(&qe->node);
|
|
kfree(qe);
|
|
|
|
mutex_lock(&q->sysfs_lock);
|
|
elevator_switch_mq(q, t);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
}
|
|
|
|
static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
|
|
int nr_hw_queues)
|
|
{
|
|
struct request_queue *q;
|
|
LIST_HEAD(head);
|
|
int prev_nr_hw_queues;
|
|
|
|
lockdep_assert_held(&set->tag_list_lock);
|
|
|
|
if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
|
|
nr_hw_queues = nr_cpu_ids;
|
|
if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
|
|
return;
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_freeze_queue(q);
|
|
/*
|
|
* Sync with blk_mq_queue_tag_busy_iter.
|
|
*/
|
|
synchronize_rcu();
|
|
/*
|
|
* Switch IO scheduler to 'none', cleaning up the data associated
|
|
* with the previous scheduler. We will switch back once we are done
|
|
* updating the new sw to hw queue mappings.
|
|
*/
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
if (!blk_mq_elv_switch_none(&head, q))
|
|
goto switch_back;
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_debugfs_unregister_hctxs(q);
|
|
blk_mq_sysfs_unregister(q);
|
|
}
|
|
|
|
prev_nr_hw_queues = set->nr_hw_queues;
|
|
set->nr_hw_queues = nr_hw_queues;
|
|
blk_mq_update_queue_map(set);
|
|
fallback:
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
if (q->nr_hw_queues != set->nr_hw_queues) {
|
|
pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
|
|
nr_hw_queues, prev_nr_hw_queues);
|
|
set->nr_hw_queues = prev_nr_hw_queues;
|
|
blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
|
|
goto fallback;
|
|
}
|
|
blk_mq_map_swqueue(q);
|
|
}
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_sysfs_register(q);
|
|
blk_mq_debugfs_register_hctxs(q);
|
|
}
|
|
|
|
switch_back:
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_elv_switch_back(&head, q);
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_unfreeze_queue(q);
|
|
}
|
|
|
|
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
|
|
{
|
|
mutex_lock(&set->tag_list_lock);
|
|
__blk_mq_update_nr_hw_queues(set, nr_hw_queues);
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
|
|
|
|
/* Enable polling stats and return whether they were already enabled. */
|
|
static bool blk_poll_stats_enable(struct request_queue *q)
|
|
{
|
|
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
|
|
blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS, q))
|
|
return true;
|
|
blk_stat_add_callback(q, q->poll_cb);
|
|
return false;
|
|
}
|
|
|
|
static void blk_mq_poll_stats_start(struct request_queue *q)
|
|
{
|
|
/*
|
|
* We don't arm the callback if polling stats are not enabled or the
|
|
* callback is already active.
|
|
*/
|
|
if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
|
|
blk_stat_is_active(q->poll_cb))
|
|
return;
|
|
|
|
blk_stat_activate_msecs(q->poll_cb, 100);
|
|
}
|
|
|
|
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
|
|
{
|
|
struct request_queue *q = cb->data;
|
|
int bucket;
|
|
|
|
for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) {
|
|
if (cb->stat[bucket].nr_samples)
|
|
q->poll_stat[bucket] = cb->stat[bucket];
|
|
}
|
|
}
|
|
|
|
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
unsigned long ret = 0;
|
|
int bucket;
|
|
|
|
/*
|
|
* If stats collection isn't on, don't sleep but turn it on for
|
|
* future users
|
|
*/
|
|
if (!blk_poll_stats_enable(q))
|
|
return 0;
|
|
|
|
/*
|
|
* As an optimistic guess, use half of the mean service time
|
|
* for this type of request. We can (and should) make this smarter.
|
|
* For instance, if the completion latencies are tight, we can
|
|
* get closer than just half the mean. This is especially
|
|
* important on devices where the completion latencies are longer
|
|
* than ~10 usec. We do use the stats for the relevant IO size
|
|
* if available which does lead to better estimates.
|
|
*/
|
|
bucket = blk_mq_poll_stats_bkt(rq);
|
|
if (bucket < 0)
|
|
return ret;
|
|
|
|
if (q->poll_stat[bucket].nr_samples)
|
|
ret = (q->poll_stat[bucket].mean + 1) / 2;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
struct hrtimer_sleeper hs;
|
|
enum hrtimer_mode mode;
|
|
unsigned int nsecs;
|
|
ktime_t kt;
|
|
|
|
if (rq->rq_flags & RQF_MQ_POLL_SLEPT)
|
|
return false;
|
|
|
|
/*
|
|
* If we get here, hybrid polling is enabled. Hence poll_nsec can be:
|
|
*
|
|
* 0: use half of prev avg
|
|
* >0: use this specific value
|
|
*/
|
|
if (q->poll_nsec > 0)
|
|
nsecs = q->poll_nsec;
|
|
else
|
|
nsecs = blk_mq_poll_nsecs(q, hctx, rq);
|
|
|
|
if (!nsecs)
|
|
return false;
|
|
|
|
rq->rq_flags |= RQF_MQ_POLL_SLEPT;
|
|
|
|
/*
|
|
* This will be replaced with the stats tracking code, using
|
|
* 'avg_completion_time / 2' as the pre-sleep target.
|
|
*/
|
|
kt = nsecs;
|
|
|
|
mode = HRTIMER_MODE_REL;
|
|
hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode);
|
|
hrtimer_set_expires(&hs.timer, kt);
|
|
|
|
do {
|
|
if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
|
|
break;
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
hrtimer_sleeper_start_expires(&hs, mode);
|
|
if (hs.task)
|
|
io_schedule();
|
|
hrtimer_cancel(&hs.timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
} while (hs.task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
destroy_hrtimer_on_stack(&hs.timer);
|
|
return true;
|
|
}
|
|
|
|
static bool blk_mq_poll_hybrid(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx, blk_qc_t cookie)
|
|
{
|
|
struct request *rq;
|
|
|
|
if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
|
|
return false;
|
|
|
|
if (!blk_qc_t_is_internal(cookie))
|
|
rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
|
|
else {
|
|
rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie));
|
|
/*
|
|
* With scheduling, if the request has completed, we'll
|
|
* get a NULL return here, as we clear the sched tag when
|
|
* that happens. The request still remains valid, like always,
|
|
* so we should be safe with just the NULL check.
|
|
*/
|
|
if (!rq)
|
|
return false;
|
|
}
|
|
|
|
return blk_mq_poll_hybrid_sleep(q, hctx, rq);
|
|
}
|
|
|
|
/**
|
|
* blk_poll - poll for IO completions
|
|
* @q: the queue
|
|
* @cookie: cookie passed back at IO submission time
|
|
* @spin: whether to spin for completions
|
|
*
|
|
* Description:
|
|
* Poll for completions on the passed in queue. Returns number of
|
|
* completed entries found. If @spin is true, then blk_poll will continue
|
|
* looping until at least one completion is found, unless the task is
|
|
* otherwise marked running (or we need to reschedule).
|
|
*/
|
|
int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
long state;
|
|
|
|
if (!blk_qc_t_valid(cookie) ||
|
|
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
|
|
return 0;
|
|
|
|
if (current->plug)
|
|
blk_flush_plug_list(current->plug, false);
|
|
|
|
hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
|
|
|
|
/*
|
|
* If we sleep, have the caller restart the poll loop to reset
|
|
* the state. Like for the other success return cases, the
|
|
* caller is responsible for checking if the IO completed. If
|
|
* the IO isn't complete, we'll get called again and will go
|
|
* straight to the busy poll loop.
|
|
*/
|
|
if (blk_mq_poll_hybrid(q, hctx, cookie))
|
|
return 1;
|
|
|
|
hctx->poll_considered++;
|
|
|
|
state = current->state;
|
|
do {
|
|
int ret;
|
|
|
|
hctx->poll_invoked++;
|
|
|
|
ret = q->mq_ops->poll(hctx);
|
|
if (ret > 0) {
|
|
hctx->poll_success++;
|
|
__set_current_state(TASK_RUNNING);
|
|
return ret;
|
|
}
|
|
|
|
if (signal_pending_state(state, current))
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
if (current->state == TASK_RUNNING)
|
|
return 1;
|
|
if (ret < 0 || !spin)
|
|
break;
|
|
cpu_relax();
|
|
} while (!need_resched());
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_poll);
|
|
|
|
unsigned int blk_mq_rq_cpu(struct request *rq)
|
|
{
|
|
return rq->mq_ctx->cpu;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_rq_cpu);
|
|
|
|
static int __init blk_mq_init(void)
|
|
{
|
|
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
|
|
blk_mq_hctx_notify_dead);
|
|
return 0;
|
|
}
|
|
subsys_initcall(blk_mq_init);
|